Evidence from several surveys indicates that posttraumatic stress disorder (PTSD) may be one of the most widespread psychiatric problems in the USA, and that a sizeable proportion of PTSD cases may arise secondary to motor vehicle accidents (MVAs). To date, the published reports of treatment with this population have been uncontrolled, with the exception of one controlled early intervention trial which failed to find an advantage of brief treatment over no treatment. (The latter finding may be due to a fairly sizeable spontaneous remission rate over the first 6 to 9 months post-MVA, identified in the work of the investigators submitting this proposal.) Other controlled evaluations of treatment of PTSD have focused on very chronic cases such as Vietnam veterans and on rape victims. These investigators propose to evaluate a brief (ten session) multicomponent cognitive behavioral treatment regimen which they have piloted, administered by experienced community-based therapists, in comparison to a brief (ten session) supportive psychotherapy and a waiting list control, in a controlled clinical trial using 105 individuals with recent (6 to 24 months post MVA) but technically chronic PTSD or severe sub-syndromal PTSD secondary to a motor vehicle accident. The investigators will screen approximately 320 MVA victims who sought medical attention and who are less than 24 months post-MVA in order to identify and recruit the sample of 105; this will include reassessment after 6 months for recent (less than 6 month) cases. Assessors, blind to treatment condition, will evaluate all treated subjects and wait list controls at post-treatment and follow-ups of 3 and 12 months using the CAPS, LIFE, and various psychological tests. Waiting list controls will receive the cognitive behavioral treatment after their reassessment.